. >>> also, big night tonight in denver. countdown to the debate. you're looking at live pictures of the debate hall in denver right now. there we are. that's where president obama and mitt romney will face off on stage. just one moderator, jim lehrer, of pbs. >> both candidates saying for months it will be crucial. >>> also, in this half hour, in this first half, a new showdown is heating up. a tree that almost killed, well, mcsteamy as you know him from "grey's anatomy." his wife was awe alone in the backyard. a tree fell on her from the next door neighbor's yard. a big legal battle brewing. >> and the lead singh from the smashing pumpkins. >>> first, we're going to get to the latest trouble for american airlines. a story we first brought you on "good morning america." another flight was forced to make an emergency landing last night. and abc's jim avila has been tracking all of the developments. jim, good morning. >> reporter: good morning, elizabeth. american pilots could be at the bargaining table as early as today, perhaps bringing to an end a